<template>
  <el-container class="home_container">
    <!-- 头部区域 -->
    <el-header>
      <div>
        <img src="../assets/heima.png" alt="" />
        <span>电商后台管理系统</span>
      </div>
      <el-button type="info" @click="logout">退出</el-button>
    </el-header>
    <!-- 页面主体 -->
    <el-container>
      <!-- 侧边栏 -->
      <el-aside width="isCollapse ?'64px':'200px' ">
        <!-- 折叠按钮 -->
        <div class="toggle_button" @click="toggleCollapse">|||</div>
        <!-- 侧边栏菜单区 -->
        <el-menu background-color="#333744" text-color="#fff" active-text-color="#409eff" unique-opened :collapse="isCollapse" :collapse-transition="false" router :default-active="activePath">
          <!-- 一级菜单 -->
          <!-- 点击一个外层菜单栏，所有的菜单栏都会打开。因此每个外层菜单栏都应该有一个独属于自己的index，index只接收字符串 -->
          <el-submenu :index="item.id + ''" v-for="item in menulist" :key="item.id">
            <!-- 一级菜单模板区 -->
            <template slot="title">
              <!-- 图标 -->
              <i :class="iconsObj[item.id]"></i>
              <!-- 文本 -->
              <span>{{ item.authName }}</span>
            </template>
            <!-- 二级菜单 -->
            <!-- 循环一级菜单的chilren -->
            <el-menu-item :index="'/' + subItem.path" v-for="subItem in item.children" :key="subItem.id" @click="saveNavState('/' + subItem.path)">
              <!-- 二级菜单模板区 -->
              <template slot="title">
                <!-- 图标 -->
                <i class="el-icon-menu"></i>
                <!-- 文本 -->
                <span>{{ subItem.authName }}</span>
              </template>
            </el-menu-item>
          </el-submenu>
        </el-menu>
      </el-aside>
      <!-- 右侧主体内容 -->
      <el-main>
        <!-- home子组件的路由占位符 -->
        <router-view></router-view>
      </el-main>
    </el-container>
  </el-container>
</template>

<script>
export default {
  data() {
    return {
      //左侧菜单数据
      menulist: [],
      iconsObj: {
        // 定义一个对象，key为一级菜单的id,value为图标
        125: 'iconfont icon-user',
        103: 'iconfont icon-tijikongjian',
        101: 'iconfont icon-shangpin',
        102: 'iconfont icon-danju',
        145: 'iconfont icon-baobiao'
      },
      //是否折叠
      isCollapse: false,
      //被激活高亮的链接地址
      activePath: ''
    }
  },
  created() {
    this.getMenuList()
    this.activePath = window.sessionStorage.getItem('activePath')
  },
  methods: {
    logout() {
      // 清空token
      window.sessionStorage.clear()
      //重定向到登陆页面
      this.$router.push('/login')
    },
    // 获取所有左侧菜单1.4.2
    async getMenuList() {
      //因为get函数返回值是个promise函数，所以await..然后通过解构赋值获取data属性
      const { data: res } = await this.$http.get('menus')
      //如果获取失败
      if (res.meta.status !== 200) return this.$message.error(res.meta.msg)
      //获取成功
      this.menulist = res.data
      //console.log(res)
    },
    //点击按钮，切换菜单的折叠与展开
    toggleCollapse() {
      this.isCollapse = !this.isCollapse
    },
    //保存二级菜单链接的激活状态
    saveNavState(activePath) {
      window.sessionStorage.setItem('activePath', activePath)
      this.activePath = activePath
    }
  }
}
</script>

<style lang="less" scoped>
// ui组件名称就是一个类选择器
.home_container {
  height: 100%;
}
.el-header {
  background-color: #373d41;
  color: #fff;
  font-size: 20px;
  display: flex;
  // 两边对齐
  justify-content: space-between;
  // 左边靠边
  padding-left: 0;
  // 按钮上下居中
  align-items: center;
  > div {
    display: flex;
    align-items: center;
    span {
      margin-left: 15px;
    }
  }
}
.el-aside {
  background-color: #333744;
  .el-menu {
    // 如果去掉这个属性，右边的线就不齐
    border-right: none;
  }
}
.el-main {
  background-color: #eaedf1;
}
.iconfont {
  margin-right: 10px;
}
.toggle_button {
  background-color: #4a5064;
  font-size: 10px;
  line-height: 24px;
  color: #fff;
  text-align: center;
  // 三条线之间有间距
  letter-spacing: 0.2em;
  // 鼠标放上去变成小手
  cursor: pointer;
}
</style>
